Funding for this research was provided by:
Japan Society for the Promotion of Science (25291103, 19J12435)
Japan Society for the Promotion of Science (21H02570)
Received: 12 January 2021
Accepted: 25 August 2021
First Online: 22 September 2021
: This study was approved by the National Health Ethics & Research Committee of Tonga, and the Research Ethics Committees of The University of Tokyo and of the Faculty of Medicine, The University of Tokyo. A written informed consent was obtained from each participant.
: Not applicable.
: The authors declare no competing interests.